A simple mission really, all you have to do is follow the red markers while being chased by the police. You shouldn't have any problems at all in this mission. Just make sure you keep your speed up when you're on the rail tracks, however the game even tells you this when you reach them. After you've lost the cops, return to the donut shop and talk to the manager.
You can now buy the store for $200,000. If you have Montana Holdings it will cost you $180,000.